The invention relates to a conveyor device for position-precisely moving objects on a conveyor surface of the conveyor device, with a plurality of forward feed elements for taking hold of the objects by their rear bottom edge in relation to the forward direction.
In particular, the invention relates to a device for position-precisely aligning conveyed objects in relation to the conveyor surface, i.e. irrespective of any actual conveyor movement. In this context one should think of instances in which the conveyor itself is switched off, and the objects have to be moved to certain specified positions, or instances in which the objects have to be moved up against a stop projecting up out of the conveyor surface.
There already exist a range of prior art conveyor systems comprising a row of conveyor belts or roller conveyors or such like spaced at intervals, between which separate stops, forward feed elements and such like can be raised and lowered. This invention is basically also intended to build on on a system of this type.
The particular task of the invention is to provide a conveyor device of the above-mentioned type which, at little constructive cost, allows the forward feed elements to be brought into the starting position using what conveyor drive means are essentially available anyway, so that the actual forward feed movement can then be carried out.
According to the invention, this task is solved with a conveyor device of the above type in that tension members, which are endless or connected via the forward feed elements to an endless strand, are provided for the purpose of moving the forward feed elements, in that the tension members for moving the forward feed elements into a specified starting position can be driven by means of a common shaft to be coupled separately with the tension members, and in that when the forward feed elements are in the specified starting position, the tension members can be uncoupled from the common shaft and each coupled with a separate linear drive with the stroke of the desired length of displacement of the objects.
Said common shaft can be the shaft which drives the actual conveyor, i.e. which sets in motion parallel conveyor belts, roller conveyors or similar. This shaft, which can in turn be rotated by a single common motor, can be coupled with the tension members of the forward feed elements with the help of couplings, and can move the forward feed elements in such a way that they arrive in the desired specified starting position. Here the tension members are uncoupled from the shaft and recoupled with a stationary, simple linear drive such as an air cylinder, which then executes the desired forward movement.
Therefore, since the only thing needed to move the forward feed elements into the starting position is an additional belt pulley with coupling on the common drive shaft of the actual conveyor, with the actual forward movement being executed by means of simple, stationary air cylinders that do not, therefore, have to be dragged along as an inert weight, the additional constructive cost compared to a simple conveyor is low. Neither is it necessary according to this invention to run power lines to drive the forward feed elements.
If several adjacent forward feed elements have to be brought into starting positions, i.e. the object to be conveyed runs with its rear bottom edge at a right angle to the conveying direction, all the forward feed elements can be brought into position at the same time. If the rear edge runs at an oblique angle to the conveying direction, the individual tension members are consecutively coupled to the common shaft and the forward feed elements are brought into position one after the other. The linear drives, in particular air cylinders, can always remain in their stationary position, because they can take hold of the tension members in any position.
Other fluid cylinders, and possibly also hydraulic cylinders or spindle drives, can be used instead of air cylinders.
These linear drives, e.g. in the form of air cylinders, preferably have one end, i.e. the cylinder or the piston, mounted such that it is stationary, whilst the other end is connected with a coupling which is displaceably guided along the base, which allows the corresponding end of the linear drive to be rigidly connected with the tension member so that the tension member can be moved to and fro by the linear drive.
The tension member is preferably an endless tension member, in particular a belt, and, especially advantageously, a toothed belt. The coupling for connecting the linear drive and the tension member is preferably elastically pre-tensioned in the engagement position, and is uncoupled by air pressure, or hydraulically.